While bats are generally not as dangerous or frightening as some people think, they can be a nuisance if they nest in trees on your property. Bats are noisy before they leave at dusk to hunt and when they return at dawn. The odor from bat droppings and urine can be overpowering, and if guano is allowed to accumulate, it attracts cockroaches and flies. Luckily, there are safe and humane ways to keep bats from nesting in your trees. Just check your state and local laws before attempting them as, in some places, removing bats is illegal.
Remove or cover any water source. Bats are attracted to water and will nest in trees to be close to it. If you have a birdbath, a small pond or a water barrel, cover or remove it from your garden.
Cover, block or remove any potential roosting sites. Bats may be attracted to holes in decaying trees or to a pile of logs under an overhanging tree. Chop down dead trees and block access to any dark and secluded holes, thus making the area less inviting to a bat colony.
Cut your lawn short and do not plant many varieties of fragrant flowers. Insects are attracted to areas with overgrown foliage and sweet-smelling flowers, and bats are attracted to places with lots of insects.
Keep outside lights to a minimum at night. The more light you have shining on your yard, the more attractive it is to night-flying insects, which will draw bats to your property.
Construct a bat house. If you do not mind bats living in your garden, but just do not want them roosting in your trees, build a bat house and locate it as far away from your house and trees as possible. Bats living in a bat house will offer the benefit of keeping insects at bay without the negatives that can sometimes come with them.